A power sander generally has a housing and a sanding plate mounted below the housing. A motor and transmission are located within the housing, and the sanding plate is connected to an output end of the transmission. In order to use the power sander, sanding paper is attached to the bottom of the sanding plate.
As is well known to those of ordinary skill in the art, prior sanding plates were fixed to the housing and as a result the abrasion level of the sanding paper would be inconsistent due to the different forces applied to the sander during use. As a result of the different forces, the usage life of the sanding paper would be decreased. In order to prolong the usage life of the sanding paper, the prior art required a user to frequently change or rotate the mounting position of the sanding paper. As a result, not only was the replacement of the sanding paper a difficult process, but it also diminished the length of use of the sanding paper.
Chinese Patent No. 9228886, discloses a sander with a rotatable sanding plate. By using the rotatable sanding plate, the usage time of the sanding plate increased and the efficiency of the sander was improved. However, the sanding plate was retained only by a spring or a steel ball. As a result, if the sander was used for a long time or was used under heavy load conditions, the sanding plate would easily shift from the pre-set direction relative to the sander which would negatively impact the normal operation by a user.